replacement wilo solar pump circulating pump yonos para st15 7 pwm2Solar pump Hydra GPS II 20 8 130 PWM2 Solar pump with PWM control The Hydra GPS is an electronic and energy efficient pump with high efficiency. The pump is designed for solar heating applications. It is controlled via an external PWM signal (stepless speed control), which ensures maximum energy yield. Advantages: EEI0. 21 Permanent magnet motor Low noise level Fixed speed mode Pump control via an external PWM signal (rising characteristic curve)